Hybrid introgression is the introduction of genes from the gene pool of one species into that of another, when the two species interbreed and produce offspring (hybridization) that are fertile, and the hybrid offspring continue to interbreed with one of the species. An interesting case of hybrid introgression is the Propertius Duskywing butterfly (Erynnis propertius). The overall range is the west coast of North America from San Diego north to central Vancouver Island, and DNA testing has found that the DNA is reasonably similar over that entire range (except for some subspecies-level variation). However, populations from southern Vancouver Island and Puget Sound have two gene structures with about a 5% difference -- which is usually a large enough difference to indicate that two species are present. One gene structure matches the rest of the Propertius Duskywing and one matches Horace's Duskywing (E. horatius) of eastern North America. At some undetermined time in the past, the range of the two species touched in the Puget Sound area, and they hybridized without merging into one species. The range of Horace's Duskywing then retreated to east of the Rockies, but left behind some of its genetic material in the Propertius Duskywing gene pool. The wing patterns and genitalia structure of the Propertius Duskywing all look the same, so the past hybridization is only detectable through DNA analysis. Quite cool!

Visit the E-Fauna BC atlas pages to learn about BC butterflies.Read the E-Fauna BC Introduction to the Butterflies by Cris Guppy.

Cris Guppy is a wildlife biologist and butterfly researcher based in the Yukon. He is co-author (with Jon Shepard) of Butterflies of British Columbia and is the butterfly advisor and butterfly photo reviewer on E-Fauna BC.

Saturday, April 12, 2014

I was on the rocky shore to the west of Kits beach (down the steps
at the end of Trutch Street) and I noticed that there is very little
life in the tide pools other than algae and mussels. I didn't see any
snails or hermit crabs at all. Is this natural for this area or have the
snails, hermit crabs and other littoral zone life been killed by
pollution?

Thank you,

Bob

3/4/14

Answer (by Tom Carefoot)

The beach in question is part of a sandstone outcropping that extends
from the Alma Street area eastwards. It is characterised by shallow
depressions with loose rocks (and other "moveable objects"). There is
nothing wrong with the water quality in the area, and further east the
shore becomes quite rich with intertidal flora and fauna. Still, with
rocks and sediments moving in the waves, there is little chance of
anything delicate surviving on the Trutch-street beach, and hermit crabs
and crabs in general would also not like the shifting substratum. As
you note, shells would likely be a resource in short supply for any
would-be hermit-crab colonisers. You may have noticed at least a few
winkles Littorina spp. higher up on the shore, but the larger dogwhelks Nucella lamellosa, whose
shells would be of a more suitable habitable size than those of
winkles, are absent from most Vancouver shores. They used to be
extremely common in the Harbour side of Stanley Park, but tributyltin
present in the water likely killed them off. You may know that this
latter, a component of older anti-fouling paints, and quite effective in
preventing barnacles and such from settling, is now banned from inshore
waters of most countries in the world. Its problem, discovered only in
the 1980s, was that it created a condition in whelks known as imposex. This refers to the masculinisation of females, or imposition
of maleness in the females leading, within a few generations, to total
sterilisation of a population. I haven't been down to the Park to check
on them for several years, so a visit to the beach near the HMCS
Discovery site might be something useful to do. The winkles mentioned
above comprise two common species Littorina scutulataand L. sitkana. These
are high-intertidal dwelling herbivorous species, sometimes even
supratidal, and are too small to eat (winkle-"picking" is a respectable
profession on Atlantic shores and in Europe). However, thanks probably
to release by winkle-eaters who can purchase live east-coast Littorina littoreafrom
several seafood-supply stores in Vancouver, this much larger and quite
tasty species can now be found on some local Vancouver beaches. It
lives in the intertidal zone, much lower than the indigenous species
just mentioned, and (should you be wondering) is unlikely to enter into
direct competition with them. Well, you probably have much more
information here than you really wanted, but it's easy to ramble on about
topics dealing with marine invertebrates.

If you have the inclination, you can get more information on imposex on A Snails Odyssey website.

Also, you can read more about littorines & relatives on A Snail's Odyssey. The information presented there mainly relates
to information published by Dr. Chris Harley of the University of
British Columbia who, along with his students, first noticed the
presence of L. littorea on local beaches.

Tom Carefoot is Professor Emeritus, Department of Zoology, University of British Columbia and is also the author of A Snail's Odyssey, a comprehensive, research-based site dedicated to marine invertebrates. Tom is a frequent contributor to E-Fauna BC.

Friday, April 4, 2014

The numbers are now in! Our regional atlases of BC's flora and fauna--E-Flora BC and E-Fauna BC--are now drawing more than half a million visits a year! Most of our visitors are from Canada, and the US, but there are many other countries represented. Many visitors are accessing the home page and searching for species information from there (~300,000) but a large number go directly to a species atlas page (400,000). Based on the comments and inquiries we receive, our users include researchers, schools/students, government, conservation groups, and the general public.

The most popular group in the atlases? Spiders! The interest in spiders is high and everyone wants to know about Brown Recluse spiders (not found in BC), Black Widow Spiders and the Giant House Spider. But, based on feedback, visitors are also keen on freshwater crustaceans, big furry wildlife (bears, wolves and cougars), and marine invertebrates (shorelines and tidal pool creataures). In the plant world, listed species and invasive species are the big attractors. The photo galleries on both sites are heavily used by visitors aiming to identify what they've found.

Our blog is drawing a lot of interest, too, with up to 3000 visitors per month. The most popular blog posts are, of course, spiders. Robb Bennett's insights into our BC spiders are always a hit, but Tom Carefoot's blog posts on 'things marine' attract lots of visitors too. There is also a lot of interest in Ian Gardiner's finds in freshwater lakes in BC: the fairy shrimp, brine shrimp and water fleas.

Interesting Facts:

The highest number of visitors to our blog in one day? 3897.

Most commonly used browser? Firefox, followed by Chrome. The use of mobile devices and associated browsers is growing and now representing 10% of our visitors consistently.

Other Biodiversity Web Sites in BC

Accidental Species in BC

The fauna of British Columbia consists of a complement of species that include BC in their natural range or distribution. But occasionally other species find their way to BC. Recently sighted accidental species in BC include the Ribbon Seal, the Red-Flanked Bluetail, and the Olive Ridley Sea Turtle. Click on the links to read about them on E-Fauna BC.